Openair-Plasma® before conformal coating: Extends the process window and ensures perfect quality

With electronic components increasingly being used in less controllable environments, the demand for (corrosion) protection is growing. From vehicle interiors and engine compartments in automotive to military and aerospace equipment – the use of a conformal coating to protect the electronics is now virtually imperative. This is the only way to safely ensure the required performance and reliability for the entire life of the PCB and beyond.
Pretreatment with Openair-Plasma® facilitates the complex process of conformal coating by extending the process window and increasing the quality of the coating.

Openair-Plasma® process

Openair-Plasma® is used to modify surface characteristics so as to enhance the adhesion of materials (such as coatings) to the substrate (PCB). It removes all organic and silicone-based impurities. Oxygen in the form of hydroxyl and ketone groups are incorporated into non-polar surfaces to activate the surface. The result is high surface energy (over 72mN/m) and in most cases, complete wettability.

Before plasma treatment: Low surface energy, higher contact angle (α > 90°) approx. 20mN/m
After Plasma treatment: Higher surface energy, lower contact angle (α < 20°) approx. 60mN/m

Coating challenges

Common issues in the conformal coating process are orange peel, bubbles, delamination, uneven coatings and cracks. These may be caused by the coating material, the circuit board, the component quality, the oven profile, impurities or even the application process.

Orange peel

The solution – Openair-Plasma®

Pretreatment with Openair-Plasma® will help to eleminate these challenges and ensures a high quality and reliable end product. Increased surface energy allows the coating material to flow more evenly and prevents the formation of bubbles. Improved adhesion of the coating combined with plasma fine-cleaning safely prevents delamination or dewetting.

Without plasma pretreatment: Delamination effect after thermal shock test
No delamination effect after plasma pretreatment
Without plasma pretreatment: Poor coverage
Complete coverage after Openair-Plasma® activation

Benefits of Openair-Plasma® technology

  • Selective: switch on and off on the fly
  • Environmentally friendly: no wet chemicals required
  • Cost-effective: operates with oil-free compressed air
  • In-line capability: no effect on process time because the plasma process takes less time than the conformal coating process


We are looking forward to your inquiry

In case of questions or suggestions, we are happy to help you. We look forward to your challenge. Here you find your personal contact for your inquiry.